In 2025, fire departments serving Mercer responded to 10 fire and hazmat incidents — from cooking fires to gas leaks to a single $25K building blaze. Here's the full picture.
Incomplete 2025 data. Mercer's departments reported 10 incidents to NFIRS for 2025, against about 19 in a typical year, so 2025 figures on this page undercount. The 2021–2025 totals are the better guide.
Power line down lead by count. Building fires lead by dollars. Together the top five categories make up about 80% of all calls.
Nov peaks. Jan dips. Watch for the typical fall climb starting in October.
93 incidents 2021–2025. Peak year was 2023. $410K cumulative property loss. 2 civilian deaths.
| Year | Incidents | YoY | |
|---|---|---|---|
| 2021 | 22 | — | |
| 2022 | 21 | -4.5% | |
| 2023 | 24 | +14.3% | |
| 2024 | 16 | -33.3% | |
| 2025* | 10 | — |
* Well below Mercer's usual volume. That almost always means one or more departments didn't submit a full year to NFIRS, not that fires dropped, so no year-over-year change is shown for it.
For the 2 building fires Mercer departments responded to in 2025, here's how they were classified once investigators were finished.
NFIRS Area of Origin (AREA_ORIG) for the 28 building fires investigators classified across 2021–2025. The room or location where ignition occurred — kitchens, bedrooms, exterior, vehicle areas — tells you where to focus prevention.
| # | Area of origin | Count | Share | |
|---|---|---|---|---|
| 1 | Undetermined | 8 | 28.6% | |
| 2 | Common room, den, family room, living room, lounge | 5 | 17.9% | |
| 3 | Engine area, running gear, wheel area | 5 | 17.9% | |
| 4 | Other | 2 | 7.1% | |
| 5 | Function area, other | 1 | 3.6% | |
| 6 | Bedroom - < 5 persons; included are jail or prison | 1 | 3.6% | |
| 7 | Laundry area, wash house (laundry) | 1 | 3.6% | |
| 8 | Equipment or service area, other | 1 | 3.6% | |
| 9 | Wall assembly | 1 | 3.6% | |
| 10 | Exterior, exposed surface | 1 | 3.6% | |
| 11 | All other areas | 2 | 7.1% |
NFIRS Heat Source (HEAT_SOURC) — the physical thing that started it. Spark or ember from operating equipment, an open flame, smoking materials, or hot embers from a fireplace are the leading culprits nationwide. Here's the Mercer mix.
| # | Heat source | Count | Share | |
|---|---|---|---|---|
| 1 | Undetermined | 17 | 60.7% | |
| 2 | Heat source: other | 5 | 17.9% | |
| 3 | Heat from powered equipment, other | 2 | 7.1% | |
| 4 | Arcing | 1 | 3.6% | |
| 5 | Hot or smoldering object, other | 1 | 3.6% | |
| 6 | Heat, spark from friction | 1 | 3.6% | |
| 7 | Flame/torch used for lighting | 1 | 3.6% |
Largest single-incident property losses reported by Mercer departments in 2025. These 4 fires alone account for 100% of the city's annual total.
| # | Property loss | Type | Severity | Status |
|---|---|---|---|---|
| 1 | $25,000 | Fire, other | Significant | Investigated |
| 2 | $10,000 | Building fires | Significant | Investigated |
| 3 | $5,000 | Building fires | Significant | Investigated |
| 4 | $4,000 | Passenger vehicle fire | Significant | Investigated |
Per-capita rates let us compare apples to apples. Mercer sits above the national average for incidents per resident.
Top 25 wildfires (1992+) in the FPA-FOD ignitions database, scaled by acres. 1,167 acres burned in this 50-mile radius. Each dot is a fire — bigger dots burned more land.
| Year | Cause | Acres | Distance | |
|---|---|---|---|---|
| 2007 | Missing data/not specified/undetermined | 120 | 25.2 mi | |
| 2006 | Natural | 80 | 14.1 mi | |
| 2000 | Natural | 79 | 13.0 mi | |
| 2012 | Power generation/transmission/distribution | 72 | 33.7 mi | |
| 2007 | Missing data/not specified/undetermined | 67 | 12.2 mi | |
| 1998 | Fireworks | 48 | 47.7 mi | |
| 1998 | Missing data/not specified/undetermined | 47 | 45.1 mi | |
| 2000 | Railroad operations and maintenance | 46 | 44.4 mi | |
| 1998 | Equipment and vehicle use | 46 | 36.1 mi | |
| 2012 | Fireworks | 45 | 43.5 mi | |
| 2009 | Debris and open burning | 45 | 39.1 mi | |
| 1994 | Arson/incendiarism | 43 | 41.9 mi |
Top 2 ZIP codes by NFIRS incident count across 2021–2025. Each ZIP has its own fire profile — dive in for neighborhood-level context.
Six Wisconsin cities with population within ±25% of Mercer. Useful comparison targets — same state, similar size, different fire profile.
1 departments report to NFIRS for incidents in Mercer.
A 30-minute weekend can cut your home's exposure substantially. These four checklists are a good starting point.
Numbers reflect incidents reported by participating fire departments to the National Fire Incident Reporting System (NFIRS) Public Data Release for calendar year 2025. NFIRS is voluntary — about 23,000 of roughly 30,000 US fire departments report — so totals are a strong indicator, not a complete census. Per-capita comparisons use 2023 ACS population estimates. Wildland fire data complements NFIRS with NIFC and USFS perimeters. Active-fire counts come from a dated NIFC snapshot, not a live feed.